From mboxrd@z Thu Jan 1 00:00:00 1970 From: charu@ti.com (Varadarajan, Charulatha) Date: Wed, 13 Oct 2010 16:25:08 +0530 Subject: [PATCHv2 1/1] omap: Ptr "isr_reg" tracked as NULL was dereferenced In-Reply-To: <7bb69801f49283c3bde78aa008c15308ac8a5fbf.1286961160.git.EXT-Eugeny.Kuznetsov@nokia.com> References: <7bb69801f49283c3bde78aa008c15308ac8a5fbf.1286961160.git.EXT-Eugeny.Kuznetsov@nokia.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > -----Original Message----- > From: Evgeny Kuznetsov [mailto:EXT-Eugeny.Kuznetsov at nokia.com] > Sent: Wednesday, October 13, 2010 3:35 PM > To: tony at atomide.com > Cc: linux-omap at vger.kernel.org; linux-kernel at vger.kernel.org; linux-arm- > kernel at lists.infradead.org; Balbi, Felipe; linux at arm.linux.org.uk; > khilman at deeprootsystems.com; akpm at linux-foundation.org; Varadarajan, > Charulatha; tero.kristo at nokia.com; ext-eugeny.kuznetsov at nokia.com > Subject: [PATCHv2 1/1] omap: Ptr "isr_reg" tracked as NULL was > dereferenced > > From: Evgeny Kuznetsov > > Value of "isr_reg" pointer is depend on configuration and GPIO method. > Potentially it may have NULL value and it is dereferenced later > in code. If pointer is NULL there is some kernel issue. Can you elaborate? > Warning and exit from function are added in this case. > Also compilation check is added for correct architecture > configuration. > > Signed-off-by: Evgeny Kuznetsov > --- > arch/arm/plat-omap/gpio.c | 18 ++++++++++++++++++ > 1 files changed, 18 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/plat-omap/gpio.c b/arch/arm/plat-omap/gpio.c > index c05c653..d04913c 100644 > --- a/arch/arm/plat-omap/gpio.c > +++ b/arch/arm/plat-omap/gpio.c > @@ -1318,6 +1318,23 @@ static void gpio_irq_handler(unsigned int irq, > struct irq_desc *desc) > if (bank->method == METHOD_GPIO_44XX) > isr_reg = bank->base + OMAP4_GPIO_IRQSTATUS0; > #endif > + > +#if !defined(CONFIG_ARCH_OMAP1) && \ > + !defined(CONFIG_ARCH_OMAP15XX) && \ > + !defined(CONFIG_ARCH_OMAP16XX) && \ > + !defined(CONFIG_ARCH_OMAP730) && \ > + !defined(CONFIG_ARCH_OMAP850) && \ > + !defined(CONFIG_ARCH_OMAP2) && \ > + !defined(CONFIG_ARCH_OMAP3) && \ > + !defined(CONFIG_ARCH_OMAP4) > + > +#error "Incorrect arch configuration" This is not required. If the architecture is not one of the above mentioned, gpio_irq_handler() will not be used/called at all. Also all the possible gpio methods for a given OMAP architecture are already considered with "#ifdef"s and (bank->method) checks in gpio_irq_handler(). > + > +#endif > + > + if (WARN_ON(!isr_reg)) > + goto exit; For the above mentioned reason, this isr_reg would be non-NULL. Have you observed this error anytime? Also, the omap-gpio code has similar code spread all over and has to be anyway cleaned-up. Is there any reason why gpio_irq_handler() alone is addressed in this patch? > + > while(1) { > u32 isr_saved, level_mask = 0; > u32 enabled; > @@ -1377,6 +1394,7 @@ static void gpio_irq_handler(unsigned int irq, > struct irq_desc *desc) > configured, we must unmask the bank interrupt only after > handler(s) are executed in order to avoid spurious bank > interrupt */ > +exit: > if (!unmasked) > desc->chip->unmask(irq); > > -- > 1.6.3.3